1. Field
Exemplary embodiments of the present invention relate to a memory device, and more particularly, to a technology for transferring data stored in a non-volatile memory in a memory device to other regions of the memory device.
2. Description of the Related Art
FIG. 1 is a block view illustrating a repair operation of a conventional memory device.
Referring to FIG. 1, the memory device includes a cell array 110 including a plurality of memory cells, a row circuit 120 for enabling a selected word line that is selected based on a row address R_ADD, and a column circuit 130 for accessing (which means reading or writing) the data of a selected bit line that is selected based on a column address C_ADD.
A row fuse circuit 140 may store a row address corresponding to a failed memory cell of the cell array 110 as a repair row address REPAIR_R_ADD. A row comparison circuit 150 may compare the repair row address REPAIR_R_ADD stored in the row fuse circuit 140 with the row address R_ADD inputted from the source other than the memory device. If the repair row address REPAIR_R_ADD and the row address R_ADD are the same, the row comparison circuit 150 may control the row circuit 120 to enable a redundancy word line instead of the word line designated by the row address R_ADD.
A column fuse circuit 160 may store a column address corresponding to a failure memory cell of the cell array 110 as a repair column address REPAIR_C_ADD. A column comparison circuit 170 may compare the repair column address REPAIR_C_ADD stored in the column fuse circuit 160 with a column address C_ADD inputted from the source other than the memory device. If the repair column address REPAIR_C_ADD and the column address C_ADD are the same, the column comparison circuit 170 may control the column circuit 130 to enable a redundant bit line instead of the bit line designated by the column address C_ADD.
The row fuse circuit 140 and the column fuse circuit 160 use laser fuses. The laser fuses may store data of a logical high level or a logical low level according to whether a fuse is cut or not. A laser fuse may be programmed in the stage of wafer, but it may not be programmed after the wafer is mounted in the inside of a package. Also, a size of laser fuse may not be reduced due to technical limitation in pitch. To overcome these concerns, an e-fuse is used. An e-fuse is formed of a transistor or a capacitor or a resistor, and an e-fuse may operate as a capacitor or a resistor. When an e-fuse is formed of a transistor, it may store a data by changing the resistance between a gate and a drain/source.
FIG. 2 is a schematic diagram illustrating an e-fuse formed of a transistor, which operates as a resistor or a capacitor.
Referring to FIG. 2, the e-fuse is formed of a transistor T, and when a low power source voltage that the transistor T may tolerate is supplied to the gate G, the e-fuse operates as a capacitor C. Therefore, no current flows between the gate G and the drain/source D/S. However, when a high power source voltage that the transistor T may not tolerate is supplied to the gate G, the gate oxide of the transistor T is destroyed to short the gate G and the drain/source D/S, and the e-fuse operates as a resistor R. Therefore, current flows between the gate G and the drain/source D/S.
Based on above results, the data of the e-fuse is recognized from the resistance value between the gate G and the drain/source D/S of the e-fuse. To recognize the data of the e-fuse, (1) the size of the transistor may be enlarged so that the data may be recognized without performing a sensing operation, or (2) an amplifier may be used to recognize the data of the e-fuse by sensing the current flowing through the transistor T instead of enlarging the size of the transistor T. These two methods have limitations in terms of area because the size of the transistor T constituting the e-fuse has to be enlarged or each e-fuse has to be provided with an amplifier for amplifying data.
It is not easy to apply the e-fuse to the row fuse circuit 140 and the column fuse circuit 160 of FIG. 1 due to the aforementioned problems. U.S. Pat. Nos. 6,904,751, 6,777,757, 6,667,902, 7,173,851 and 7,269,047 disclose a technology of forming an e-fuse in an array type and performing a repair operation using the data stored in the e-fuse array. When the e-fuse is formed in an array type, the total size may be reduced because components, such as an amplifier may be shared.